Homeworld Cataclysm (like Homeworld) stores data in .big files. In order to extract these files you’ll need an extraction tool. There are several user built tools that work great. I used winbigw and had no issues with it. To extract .big files follow:

Extract a .big file! Navigate to your Cataclysm directory and open either cataclysm.big or update.big. To extract all the files into a new folder use the right most button.

cataclysm.big

cataclysm.big contains almost all the essential game files. Among these are several script files, some object files and a bunch of .shp files which contain all the object data for each ship. One thing that annoyed me about Homeworld Cataclysm was that the data source wasn’t easily accessible like it is in Homeworld 2. To aid you in this process and give you an idea of what you’re getting into, I’ve extracted some of the game’s .shp files and uploaded them into the spreadsheet below (link to spreadsheet).

Now the fun part. With with WinBigw you can recompress .big files and replace the existing ones in your installation for some potentially hilarious results (and more legitimate modding activites if you’re into that kind of thing…)

With the program open click the top left ‘New Big File’ option

Create a file named cataclysm.big

Find where you extracted the contents of cataclysm.big earlier and select that folder when the add from menu appears. Make sure there are only extracted files in this folder (no .exe files etc.)

Back up your original cataclysm.big file in your installation directory and replace it with your newly created one. Note: I would recommend you start with editing sacolyte.shp as I have. There are many different ships and some ARE NOT WHAT YOU THINK. There are plenty of neutral units, and editing these files will have no observable effect if you’re just quickly testing it out in a skrimish match.

giga-acolyte

To show what you can do with just the ship files I did a little experiment. I decided to tweak the sacolyte.shp file and create a my own new and improved Somtaaw giga-acolyte who’s only goal is to dump ridiculous amounts of slow moving bullets on the enemy. For *safety* reasons I started slow:

Not bad. Let’s try upping it to 3 bullets per second.

Just… a few more…

20 bullets a second from 142 acolytes was about as far as I could go. My pc tried to render the ensuing bullet-vomit and promptly shit the bed. Being able to edit the .shp files and re-compress them opens up a lot of interesting modding options. The only question that remains is whether or not you can make something that will stack up against a swarm of giga-acolytes. Post your ideas below!

Editing the .shp files only work if you put the files back in the installation folder, NOT back into the .big file. The game will crash if you make a new .big file with WinBigw.exe 1.0.0.14.
For example, this is what you end up with when you edit the Samtaaw mothership:
C:\Program Files (x86)\Cataclysm\race_sect\sMothership.shp